Home VTR systems such as VHS and the like, which use magnetic tape as a recording medium, have become a common feature of most households. In recent years, as personal computers become more widespread, hard disk and other recording devices have continued to become cheaper as well as expand in capacity. At the same time, in the video camera field, DV-type digital recording is becoming the standard recording format.
Against this backdrop, the digitization wave has hit home video decks as well, with products now available that record and reproduce video signals encoded in MPEG2 format to and from a hard disk (hereinafter called a disk recorder).
This type of disk recorder has many advantages over the conventional VTR, such as content management and reproduction utilizing random accessibility, extended time recording, and the ability to play back previously recorded contents while recording new matter at the same time.
With respect to a recording reservation function installed in a disk recorder of this type, an overwrite function has come to be most common.
An overwrite function is a function effective for repeated daily or weekly reserved recordings. When the overwrite function is set to engage, when executing a new program recording, a previously recorded program is erased, so as to be able to use the disk efficiently. Whether the overwrite function is engaged or disengaged can be specified with each recording reservation. When the overwrite function is turned off and a recording reservation made, past programs are saved without being erased.
Japanese Laid-Open Patent Publication No. 2000-138886 discloses a technology in which a certain specified number of recordings are always saved. For example, if four recordings are specified, then the latest program plus the last three recorded programs are saved, with the oldest program automatically erased at the next recording. In addition, Japanese Laid-Open Patent Publication No. 2002-033983 discloses a technology in which, even if the overwrite function is set to be engaged, if past programs are set to an erasure prohibited setting, or if the apparatus is in the process of recording, the past programs will not be erased.
However, there remains the problem that, when the overwrite function is engaged, past programs are erased whether or not a user has viewed them.
In order to avoid such an outcome, it is enough, of course, to disengage the overwrite function. However, in the event that the user forgets to disengage the overwrite function when setting the recording reservation time, a previously recorded program will be overwritten and thus erased.
Moreover, there remains the problem that, with the methods described in the foregoing publications, the user must set the conditions of erasure separately for each of the recorded programs, making the apparatus extremely difficult to operate.